more fancy features

pkg/inventory/redis_reservation_service.go

@@ -46,13 +46,13 @@ func totalReservedKey(sku SKU, locationID LocationID) string {
 
 func (s *RedisCartReservationService) ReserveForCart(ctx context.Context, req CartReserveRequest) error {
 	keys := []string{
-		getInventoryKey(req.Sku, req.LocationID),
-		cartQtyKey(req.Sku, req.LocationID),
-		cartExpKey(req.Sku, req.LocationID),
-		totalReservedKey(req.Sku, req.LocationID),
+		getInventoryKey(req.SKU, req.LocationID),
+		cartQtyKey(req.SKU, req.LocationID),
+		cartExpKey(req.SKU, req.LocationID),
+		totalReservedKey(req.SKU, req.LocationID),
 	}
 	args := []interface{}{
-		string(req.CartId),
+		string(req.CartID),
 		req.Quantity,
 		int64(req.TTL.Seconds()),
 	}
@@ -112,6 +112,39 @@ func (s *RedisCartReservationService) GetReservationStatus(ctx context.Context,
 	}, nil
 }
 
+func (s *RedisCartReservationService) GetReservationSummary(ctx context.Context, sku SKU, locationID LocationID) (*ReservationSummary, error) {
+	qtyKey := cartQtyKey(sku, locationID)
+	expKey := cartExpKey(sku, locationID)
+
+	// Get reservation count
+	reservationCount, err := s.client.HLen(ctx, qtyKey).Result()
+	if err != nil {
+		return nil, err
+	}
+
+	// Get earliest release (min score in sorted set)
+	minScore, err := s.client.ZRangeWithScores(ctx, expKey, 0, 0).Result()
+	if err != nil {
+		return nil, err
+	}
+	var earliestRelease time.Time
+	if len(minScore) > 0 {
+		earliestRelease = time.Unix(int64(minScore[0].Score), 0)
+	}
+
+	// Get remaining items
+	remainingItems, err := s.GetAvailableInventory(ctx, sku, locationID)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ReservationSummary{
+		ReservationCount: reservationCount,
+		EarliestRelease:  earliestRelease,
+		RemainingItems:   remainingItems,
+	}, nil
+}
+
 func (s *RedisCartReservationService) GetAvailableInventory(ctx context.Context, sku SKU, locationID LocationID) (int64, error) {
 	keys := []string{
 		getInventoryKey(sku, locationID),